Influence of Dielectric Plasma Etch Source for PHEMT Device Performance

PHEMT device parametric performance was improved by transfer from a transformer coupled plasma source to an RF helicon wave high density plasma source for the oxide dielectric etch prior to ohmic metal deposition. Process stability and uniformity were enhanced leading a higher yielding product with a wider process window. Significant improvement was measured for device parameters such as contact resistance, on resistance, and transconductance. Evaluation of etch source differences were investigated by examining surface damage.